1. Field of the Invention
THIS INVENTION relates to a pump.
The pump is particularly suitable for, but not limited to, a pump for liquids.
The term "liquid" shall be used throughout the specification to include liquids, slurries, flowable powders, flowable granular materials and the like.
The term "container" throughout the specification shall include containers, tins, drums, barrels, tanks and the like.
2. Prior Art
Many different types of pumps have been used and proposed for pumping liquids into, or out of, containers. Examples include gerotor pumps, gear pumps, Roots pumps, vane pumps, and the like.
All of these pumps have the major limitation that they require moving parts which are subject to wear, leading to loss of efficiency and requiring periodic replacement.
In an effort to overcome the use of moving parts, venturi-like pumps have been developed--U.S. Pat. Nos. 5,329,982 (PAYNE) and 3,861,830 (JOHNSON). These pumps employ a fixed venturi and valve(s) to direct pressurized air or vacuum to control the flow of liquid into, or out of, the container. This requires both a pressure source and a vacuum source to operate the pumps.